As technology has progressed, rapid prototyping methods have been developed for producing 3-D objects with various shapes. These methods shorten the time for manufacturing prototype models and also considerably reduce the labour and time involved in processing. Among the conventional rapid prototyping methods, the fused deposition modeling (FDM) method is relatively easy to master. The FDM method is a continuous repetition of the following processes: heating the material in the main body to make it flowable; discharging the heated material onto a deposition region on a substrate through an opening of the dispense head; and depositing, cooling and solidifying the discharged material. The 3-D object is then produced after printing of multiple layers as described above.
In the conventional FDM methods, the temperature of the material discharged from the printing head and then deposited on the deposition region drops quickly. Sometimes, the material discharged from the printing head cannot adequately bond to the deposited material, or even though they are bonded together, an undesired thermal stress remains in the printed 3-D object. In addition, the material may stick to the passage of the dispense head and thus hinder the feeding or discharging of the material. Based on the above, while the conventional FDM methods are generally adequate for producing a 3-D model, they have not been satisfactory in every respect.